not all web servers around the web are going to give you same speeds. use a download manager for large downloads. that's what i do. instead of staring at how fast a download is going, i just let the download manager do its thing and when the download is done, i get an alert and i get on it.
i am getting shitty upload speeds on Linode where this forum is running. i barely get 250kBps! but since the downloads are fine... i do not bother myself about it. getting any support from excitel is going to be useless. linode might be able to help out but it's unlikely they can fix this issue.
try with a VPN, try with your backup isp, contact a friend who is online to see what speed he is getting. it is usually the web server. if you have a web server, download the file first there and download your file from your own server.